Comment 37 for bug 177646

On Thu, Jan 15, 2009 at 05:38:26PM -0000, Wesley Velroij wrote:
> It has more off enough information, but I am not sure if it would really
> safe energy.

It has information to prove the option is not enabled. The option is
not enabled because it should be of no help. The CPU will be in the same
states for the same length of time overall though possibly in a slightly
different distribution, therefore power consumption is not modified.
I linked to the discussions of why how the kernel uses the various CPU
states, and how this option is not a power management option. There is
even discussion there of how enabling this would have a detremental
effect on power consumption in some use models.

The only feedback on the bug which might show an actual reduction in power
consumption was not described in enough detail to show whether the power
consumption was being measured in a truly comparible way, ie. was it an
instantaneous measurement or over the whole period of the task. The key
being overall power consume during the whole task. It was that information
which we were waiting for, and was not forthcoming. Therefore we are
in a position where the is no information to show this is a benefit,
and much to how it would likely be zero and even a negative impact.

That is what led to the closure lacking information.